Electronic weighing scales typically present the value of a weight on an electronic digital display. The latter is convenient to read and potentially capable of reading with high accuracy.
Electronic weighing scales are commercially available for a wide variety of applications; employed for weighing small weights (less than 1 gram) as well as for applications involving weights exceeding many tons. The sensor which converts the value of the weight to an electrical signal can either sense the deflection of a spring structure by an added weight, or alternatively can sense the strain in a relatively stiff spring structure by the added weight.
An important aspect of the design of the spring structure and its associated sensor is the elimination of variations of apparent weight related to the weight location on the weighing platform. This weighing error is typically reduced or eliminated in commercial designs by employing a cantilevered spring structure.
Commercial sensors for transforming spring deformation into an electrical signal are of two types depending upon whether strain or deflection of the spring structure is being sensed. Sensors employed in prior designs utilizing deflection of the spring structure are typically either the variable differential transformer or variable capacitance means; the typical sensor for measuring strain in the spring structure is the conventional strain gauge.